install_pmbootstrap.sh: is_default_channel=False

Let pmbootstrap use the channel of the currently checked out pmaports
branch, if pmaports.git exists already. Otherwise, it would try to
change to the branch of the default channel as specified in channels.cfg
(currently "edge").

install_pmbootstrap.sh

@@ -46,6 +46,12 @@ if [ -e "$pmaports/pmaports.cfg" ]; then
 		cat /tmp/git_remote_add
 		exit 1
 	fi
+
+	# Use the channel of the current branch
+	mkdir -p ~pmos/.config
+	( echo "[pmbootstrap]"
+	  echo "is_default_channel = False" ) > ~pmos/.config/pmbootstrap.cfg
+	chown -R pmos:pmos ~pmos/.config
 fi
 
 # Download pmbootstrap (to /tmp/pmbootstrap)